Add --host flag to dbt docs serve, defaulting to '127.0.0.1'

[MichelleArk]

Housekeeping

• I am a maintainer of dbt-core

Short description

As part of GHSA-pmrx-695r-4349, we explicitly set 127.0.0.1 as the default bind address for dbt docs serve. However, we did not provide the ability for users to be able to override / opt-out of the default, and the change in default caused reported breakages in user deployments (example: #10208 (comment)). Let's add that ability, and backport it :)

Acceptance criteria

dbt docs serve binds to '127.0.0.1' by default, but is possible to override via a new --host flag.

Suggested Tests

1. Test that passing an empty string is still possible for --host to restore previous behaviour
2. Test default

Impact to Other Teams

N/A

Will backports be required?

Backport 1.6.latest, Backport 1.7.latest, Backport 1.8.latest

Context

No response

[MichelleArk]

User docs: https://docs.getdbt.com/reference/commands/cmd-docs#dbt-docs-serve this section should be updated to include the new --host flag, which will default to localhost

[FishtownBuildBot]

Opened a new issue in dbt-labs/docs.getdbt.com: dbt-labs/docs.getdbt.com#5573